This invention relates to a system for treating water in a closed circulating system, and more particularly to a dispensing system for adding chemical treatment to a cooling water system for a diesel locomotive.
In a railroad locomotive, it is common to use water as an engine coolant due to well-known difficulties resulting from the use of glycol coolants or the like. In a locomotive cooling system, it is often difficult to prevent the loss of coolant water resulting from leaks or cracks within the system. As a result, it is often necessary to replenish the supply of water in the system to ensure that an adequate quantity of water is available for cooling the engine.
In a cooling system utilizing water as the coolant, it is desirable to maintain a certain level of concentration of chemical water treatment within the system to inhibit corrosion and buildup of scale within the system, as well as for other purposes. Because of the above-noted problems in maintaining an adequate quantity of water within the system, the level of concentration of the chemical treatment in the cooling water often falls below the optimal level.
Additionally, because of the nature of such a water cooling systems, when the locomotive is at rest and the ambient temperature is sufficiently low to create the potential for freezing of the water in the system, the water is dumped so as to empty the system and prevent damage which may be caused by such freezing. The cooling system is then refilled when it is desired to operate the locomotive, and it is often the case that the addition of proper chemical treatment to the water is neglected prior to operation.
As can be seen from the above, there is a need for a system which will automatically maintain a predetermined level of concentration of chemical treatment within the cooling water system. The present invention is designed to provide such an automatic system.
In accordance with the invention, an apparatus for maintaining a predetermined level of concentration of treatment chemicals or the like in a closed fluid circulating system includes a sensing means for monitoring the level of concentration of chemicals in the fluid circulating within the system. A chemical concentrate dispensing means is interconnected with the fluid circulating system. Flow control means responsive to the sensing means prevents the flow of fluid through the dispensing means when the level of concentration of chemicals in the fluid is at or above the predetermined level. When the level of concentration of treatment chemicals in the fluid falls below the predetermined level, the flow control means allows fluid from the fluid circulating system to circulate through the dispensing means and back into the fluid circulating system. In this manner, the level of concentration of chemicals in the fluid within the system is raised to the predetermined level. When the sensing means has determined that the level of concentration of the chemicals in the fluid is at or above the predetermined level, the flow control means discontinues circulation of fluid through the dispensing means.
In one embodiment, the sensing means comprises a probe for measuring the conductivity of fluid within the fluid circulating system, and thereby the level of concentration of chemicals in the fluid. A comparator is utilized for ascertaining whether, based on the conductivity reading of the fluid, the level of concentration is satisfactory. The dispensing means comprises a fluid inlet connected to the fluid circulating system for routing at least a portion of fluid from the system. A housing having an interior cavity in fluid communication with the inlet is adapted to receive fluid therefrom. A replaceable dispensing canister adapted to hold a quantity of soluble chemical treatment is disposed within the interior cavity of the housing. A passage is provided for allowing fluid to pass from the interior of the housing into the canister for mixing the fluid with the soluble chemical treatment. A passage is also provided for allowing the mixed fluid and chemical treatment to pass from the canister to a fluid outlet connected between the fluid circulating system and the passage, for routing the mixed fluid and chemical treatment back into the circulating system.
A novel design is employed for the canister located within the housing of the dispensing means. The canister is provided with a bottom wall and an upstanding side wall extending therefrom to define a canister interior having a transverse dimension less than that of the interior cavity of the housing. A fluid flow path is thus formed between the side wall of the housing and the side wall of the canister. Passage means is disposed between the fluid flow path and the interior of the canister to allow fluid to pass into the canister interior for mixing the fluid with the chemical treatment. Discharge means is in fluid communication with the canister interior for discharging mixed fluid and chemical treatment therefrom. In one embodiment, the passage means comprises a series of openings formed in the bottom wall of the canister. The fluid flows downwardly through the flow path between the canister side wall and the housing side wall to the bottom of the canister, and then upwardly through the openings and into the interior of the canister to mix with the concentrated chemical treatment contained therein. In one embodiment, the discharge means comprises a dip tube extending downwardly into the interior of the canister, and having an opening for receiving mixed fluid and chemical treatment therefrom.
The invention also incorporates a mechanism for relieving pressure within the housing of the dispensing apparatus prior to gaining access to the housing interior for replacing the canister. A line connects the housing interior to a dump valve open to ambient pressure. A switch, placed adjacent the housing, is operable to actuate the dump valve. Actuation of the dump valve relieves pressure in the housing interior prior to gaining access thereto, thereby providing a safety mechanism to prevent operator injury. The dip tube extending downwardly into the housing interior siphons a substantial quantity of liquid from the housing interior upon actuation of the dump valve, thereby providing a further mechanism for preventing operator injury. A secondary mechanism is employed for ensuring that pressure within the housing interior is relieved in the event the operator neglects to actuate the dump valve by means of the switch. A cover is mounted to the dispensing apparatus adjacent the housing and, when in a first position, prevents the operator from gaining access to the housing interior. The cover is movable to a second position for allowing access to the housing interior. A secondary switch, interconnected with the dump valve, is actuated when the cover is moved from the first position to the second position. This mechanism ensures that pressure in the housing interior is relieved prior to gaining access thereto for replacing the canister.